Method of forming structures using a neutral beam

ABSTRACT

Methods of forming structures using a neutral beam, structures formed using a neutral beam, and reactor systems for forming the structures are disclosed. The neutral beam can be used to provide activated species during deposition of a layer and/or to provide activated species to treat a deposited layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/875,892, filed on Jul. 18, 2019, in the United States Patent andTrademark Office, the disclosure of which is incorporated herein in itsentirety by reference.

FIELD OF INVENTION

The present disclosure generally relates to methods and systems forforming structures and to structures formed using the methods. Moreparticularly, the disclosure relates to methods of forming structuresusing a neutral beam, to structures formed using the methods, and tosystems for performing the methods.

BACKGROUND OF THE DISCLOSURE

Conformal film deposition may be desirable for a variety of reasons. Forexample, during the manufacture of devices, such as semiconductordevices, it is often desirable to conformally deposit material overfeatures formed on the surface of a substrate. Such techniques can beused for shallow trench isolation, inter-metal dielectric layers,passivation layers, and the like. However, with miniaturization ofdevices, it becomes increasingly difficult to conformally depositmaterial, particularly over high aspect ratio features, such as featureshaving an aspect ratio of three or more.

Atomic layer deposition (ALD) can be used to conformally depositmaterial, such as dielectric material, onto a surface of a substrate.For some applications, such as when a relatively high temperature isused for ALD deposition and/or when it is desired to keep a processingtemperature relatively low, it may be desirable to use plasma-enhancedALD (PEALD).

Unfortunately, material deposited using PEALD can exhibit relativelypoor film quality—e.g., exhibit a relatively high etch rate in a liquidor gas-phase etchant. For example, silicon oxide films deposited usingPEALD can exhibit relatively high etch rates in dilute hydrofluoric acid(e.g., 1:100 by volume HF:H₂O), compared to silicon oxide filmsdeposited without the aid of a plasma.

Accordingly, improved systems and methods for forming high-qualitymaterial, such as high-quality dielectric material (e.g., siliconoxide), on a substrate and structures formed using such methods and/orsystems are desired. Any discussion of problems and solutions describedin this section has been included solely for the purposes of providing acontext for the present invention and should not be taken as anadmission that any or all of the discussion was known at the time theinvention was made.

SUMMARY OF THE DISCLOSURE

Various embodiments of the present disclosure relate to methods offorming structures that include high-quality insulating or dielectricfilms. While the ways in which various embodiments of the presentdisclosure address drawbacks of prior methods and systems are discussedin more detail below, in general, various embodiments of the disclosureprovide improved methods that include use of a neutral beam—duringdeposition of the films, during treatment of the films, or both.

In accordance with at least one embodiment of the disclosure, a methodof forming a structure includes forming a layer, forming a neutral beam,and, exposing the layer to species generated from the neutral beam. Theneutral beam can be generated from, for example, one or more gasesselected from the group consisting of hydrogen-containing gases (e.g.,hydrogen), He, NH₃, O₂, N₂O, CO₂, Ar, Xe, N₂, and their mixture, such asone or more of H₂ and He, and particularly H₂. The layer can include,for example, one or more of an oxide, a nitride, and a carbide. By wayof examples, the layer can include one or more of SiO₂, SiN, SiOC, SiCN,SiC, SiON, SiOCN, SiBN, SiBO, GeO_(x), GeN, AlO_(X), TiO₂, and TaO₂. Thelayer can be deposited using one or more of PEALD, PECVD, NBEALD, andNBECVD. The step of forming a layer can include a cyclic depositionprocess, and the cyclic deposition process can be repeated a number ofcycles prior to the step of exposing. For example, the cyclic depositionprocess can be repeated a number of time until a thickness layer isgreater than zero and less than 10 nm, and then the layer can be exposedto species generated from the neutral beam. The step of forming a layer(e.g., cyclic deposition process that can be repeated a number of times)and the step of exposing the layer to species generated from the neutralbeam can be repeated until a desired film thickness is obtained. Thedesired film thickness can be greater than 10 nm. A temperature duringthe step of forming a layer can be less than 400° C., less than 300° C.,less than 200° C., less than 100° C., about 25° C. to less than any ofthese temperatures, about 25-40° C., about ambient temperature, about 0to about 100° C., about 0 to about 200° C., or about 0 to about 300° C.A pressure within the reaction chamber during the step of forming alayer can be between about 0.01 Pa and about 100 Pa, about 0.05 Pa andabout 1 Pa, or about 0.1 Pa and about 0.5 Pa. A pressure within thereaction chamber during the step of forming a neutral beam can bebetween about 0.01 Pa and about 100 Pa, about 0.05 Pa and about 1 Pa, orabout 0.1 Pa and about 2 Pa. A power of an RF power supply during thestep of forming a layer can be between about 0.1 W/cm² and about 20W/cm², about 0.2 W/cm² and about 10 W/cm², or about 1 W/cm² and about 5W/cm². A power of an RF power supply during the step of forming aneutral beam can be between about 0.1 W/cm² and about 20 W/cm², about 1W/cm² and about 15 W/cm², or about 3 W/cm² and about 10 W/cm². In somecases, a precursor used during the step of forming a layer can beselected from the group consisting of aminosilanes, such as BDEAS(SiH₂[N(C₂H₅)₂]₂), BTBAS (SiH₂[NHC(CH₃)₃]₂), TDMAS (SiH[N(CH₃)₂]₃), HEAD(Si₂[NHC₂H₆]₆), 3DMASCl (Si[N(CH₃)₂]₃Cl), 3EMAS (H₂Si[N(C₂H₅)CH₃]₃),4DMAS (Si[N(C₂H₆)₂])₄), 4DEAS (Si[N(C₂H₆)₂]₄), or other Si-containingprecursor, such as 4MS ((CH₃)4Si), 2ES ((C₂H₅)₂SiH₂), phenyl-SiH₃, andcyclohexyl-SiH₃, Si(OC₂H₅)₄. A bias can be applied to an aperture plateof a neutral beam apparatus during the step of forming the layer and/orduring the step of exposing the layer. The bias during the step offorming a layer can be between about 0 W/cm² and about 3 W/cm², about 0W/cm² and about 1 W/cm², or about 0 W/cm² and about 0.5 W/cm². The biasduring the step of forming a neutral beam can be between about 0 W/cm²and about 3 W/cm², about 0 W/cm² and about 1 W/cm², or about 0.05 W/cm²and about 0.2 W/cm².

In accordance with yet further exemplary embodiments of the disclosure,a method of forming a structure includes providing a substrate within areaction chamber, providing a precursor to a gas inlet of the reactionchamber to form adsorbed species on a surface of the substrate,providing a reactant to a gas inlet of a plasma chamber, forming aneutral beam from species generated in the plasma chamber, and exposingthe adsorbed species to species from the neutral beam to form a layercomprising silicon. In accordance with exemplary aspects of theseembodiments, the precursor can selected from the group consisting ofaminosilanes, such as BDEAS (SiH₂[N(C₂H₅)₂]₂), BTBAS (SiH₂[NHC(CH₃)₃]₂),TDMAS (SiH[N(CH₃)₂]₃), HEAD (Si₂[NHC₂H₆]₆), 3DMASCl (Si[N(CH₃)₂]₃Cl),3EMAS (H₂Si[N(C₂H₅)CH₃]₃), 4DMAS (Si[N(C₂H₆)₂])₄), 4DEAS(Si[N(C₂H₆)₂]₄), or other Si-containing precursors, such as 4MS((CH₃)₄Si), 2ES ((C₂H₅)₂SiH₂), phenyl-SiH₃, cyclohexyl-SiH₃, Si(OC₂H₅)₄.Exemplary reactants include one or more of oxygen, CO, CO₂, and NO₂. Inaccordance with further exemplary aspects, methods can include exposingthe layer to a neutral beam. For example, exemplary methods can includeproviding gas, such as one or more of a of hydrogen-containing gases(e.g., hydrogen), He, NH₃, O₂, N₂O, CO₂, Ar, Xe, N₂, and their mixture,such as one or more of H₂ and He, and particularly H₂, to the plasmachamber, and exposing the layer to species generated from the gas totreat the layer. Exemplary methods can include repeating the steps ofproviding the precursor to the gas inlet of the reaction chamber to formadsorbed species on a surface of the substrate, providing the reactantto the gas inlet of the plasma chamber, forming the neutral beam fromspecies generated in the plasma chamber, and exposing the adsorbedspecies to species from the neutral beam to form the layer comprisingsilicon a desired number of times. These steps may be repeated until adesired film thickness—e.g., less than 10 nm—is deposited. A step ofexposing the layer to species generated from the gas may then beperformed to treat the layer. This process of forming a layer to lessthan 10 nm and treating the layer can be repeated a number of timesuntil a desired film thickness, which can be greater than 10 nm, isobtained. A bias can be applied to an aperture plate of a neutral beamapparatus during the step of exposing the layer and/or during the stepof exposing the adsorbed species. The temperatures, pressures, and biaslevels can be the same or similar to those described above and elsewhereherein.

In accordance with yet additional examples of the disclosure, a reactorsystem is provided. The reactor system can be configured to perform amethod as described herein.

In accordance with yet further exemplary embodiments of the disclosure,a structure comprises a layer formed according to a method describedherein.

These and other embodiments will become readily apparent to thoseskilled in the art from the following detailed description of certainembodiments having reference to the attached figures; the invention notbeing limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of exemplary embodiments of the presentdisclosure can be derived by referring to the detailed description andclaims when considered in connection with the following illustrativefigures.

FIG. 1 illustrates a method in accordance with at least one embodimentof the disclosure.

FIG. 2 illustrates another method in accordance with at least oneembodiment of the disclosure.

FIG. 3 illustrates a reactor system in accordance with at least oneembodiment of the disclosure.

FIGS. 4-7 illustrate structures in accordance with exemplary embodimentsof the disclosure.

FIG. 8 illustrates a relationship between wet etching time in 0.1%hydrofluoric acid vs etching depth of hydrogen neutral beam-irradiatedNBEALD silicon oxide films.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The present disclosure generally relates to methods of formingstructures, such as structures suitable for forming electronic devices,to reactor systems for performing the methods, and to structures formedusing the methods. By way of examples, the systems and methods describedherein can be used to form conformal, high-quality insulating ordielectric layers. The insulating or dielectric layers can be depositedonto a surface of a substrate, which can include high-aspect ratiofeatures. In some cases, the layers can be formed using a cyclic processthat employs a neutral beam, such as NBEALD. In some cases, the layerscan additionally or alternatively be exposed to (i.e., treated with)activated species formed using a neutral beam to form a structureincluding high-quality layers.

In this disclosure, “gas” may include material that is a gas at roomtemperature and pressure, a vaporized solid and/or a vaporized liquid,and may be constituted by a single gas or a mixture of gases, dependingon the context. A gas other than the process gas, i.e., a gas introducedwithout passing through a gas distribution assembly, such as ashowerhead, other gas distribution device, or the like, may be used for,e.g., sealing the reaction space, and may include a seal gas, such as arare gas. In some embodiments, the term “precursor” can refer to acompound that participates in the chemical reaction that producesanother compound, and particularly to a compound that constitutes a filmmatrix or a main skeleton of a film; the term “reactant” can refer to acompound, other than precursors, that activates a precursor, modifies aprecursor, or catalyzes a reaction of a precursor, wherein the reactantmay provide an element (such as O, N, or C) to a film matrix and becomea part of the film matrix, when, for example, RF power is applied. Theterm “inert gas” can refer to a gas that does not take part in achemical reaction and/or a gas that excites a precursor when RF power isapplied, but unlike a reactant, it may not become a part of a filmmatrix to an appreciable extent. Exemplary inert gases include He, Ar,N₂ and any combination thereof.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used to form, or upon which, a device,a circuit, or a film may be formed. A substrate can include a bulkmaterial, such as silicon (e.g., single-crystal silicon), other Group IVmaterials, such as germanium, or compound semiconductor materials, suchas a Group II-VI or Group III-V semiconductor, and can include one ormore layers overlying or underlying the bulk material. Further, thesubstrate can include various features, such as recesses, lines, and thelike formed within or on at least a portion of a layer of the substrate.The feature can have relatively high aspect ratios, ranging from, forexample, about 1 to about 50 or about 3 to about 20.

As used herein, the term “film” and/or “layer” can refer to anycontinuous or non-continuous structures and material, such as materialdeposited and/or treated by the methods disclosed herein. For example,film and/or layer can include two-dimensional materials,three-dimensional materials, nanorods, nanotubes, or nanoparticles oreven partial or full molecular layers or partial or full atomic layersor clusters of atoms and/or molecules. A film or layer may comprisematerial or a layer with pinholes, which may be at least partiallycontinuous.

As used herein, the term “cyclic deposition” can refer to the sequentialintroduction of precursors (reactants) into a reaction chamber todeposit a film over a substrate and includes deposition techniques, suchas atomic layer deposition and cyclical chemical vapor deposition.

As used herein, the term “cyclical chemical vapor deposition” can referto any process wherein a substrate is sequentially exposed to two ormore volatile precursors, which react and/or decompose on a substrate toproduce a desired deposition.

As used herein, the term “atomic layer deposition” (ALD) can refer to avapor deposition process in which deposition cycles, typically aplurality of consecutive deposition cycles, are conducted in a reactionchamber. Typically, during each cycle, the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, a reactant(e.g., another precursor or reaction gas) may subsequently be introducedinto the reaction chamber for use in converting the chemisorbedprecursor to the desired material on the deposition surface. Typically,this reactant is capable of further reaction with the precursor.Further, purging steps may also be utilized during each cycle to removeexcess precursor from the reaction chamber and/or remove excess reactantand/or reaction byproducts from the reaction chamber after conversion ofthe chemisorbed precursor. Further, the term “atomic layer deposition,”as used herein, is also meant to include processes designated by relatedterms, such as chemical vapor atomic layer deposition, atomic layerepitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, ororganometallic MBE, and chemical beam epitaxy when performed withalternating pulses of precursor composition(s), reactive gas, and purge(e.g., inert carrier) gas. PEALD refers to an ALD process, in which aplasma is applied during one or more of the ALD steps.

As used here, a “structure” can include a substrate as described herein.Structures can include one or more layers, overlying the substrate,which formed and/or treated as described herein.

Further, in this disclosure, any two numbers of a variable canconstitute a workable range of the variable, and any ranges indicatedmay include or exclude the endpoints. Additionally, any values ofvariables indicated (regardless of whether they are indicated with“about” or not) may refer to precise values or approximate values andinclude equivalents, and may refer to average, median, representative,majority, etc. in some embodiments. Further, in this disclosure, theterms “including,” “constituted by” and “having” refer independently to“typically or broadly comprising,” “comprising,” “consisting essentiallyof,” or “consisting of” in some embodiments. In this disclosure, anydefined meanings do not necessarily exclude ordinary and customarymeanings in some embodiments.

In this disclosure, “continuously” can refer to one or more of withoutbreaking a vacuum, without interruption as a timeline, without anymaterial intervening step, without changing treatment conditions,immediately thereafter, as a next step, or without an interveningdiscrete physical or chemical structure between two structures otherthan the two structures in some embodiments.

Turning now to the figures, FIG. 1 illustrates a method 100 of forming astructure in accordance with at least one embodiment of the disclosure.Method 100 includes the steps of forming a layer (step 102), forming aneutral beam (step 104), and exposing the layer to species generatedfrom the neutral beam (step 106).

Step 102 can include forming an insulating or dielectric material layer.For example, step 102 can include forming one or more of an oxide, anitride, and a carbide layer. By way of particular examples, the layercan be or include one or more of SiO₂, SiN, SiOC, SiCN, SiC, SiON,SiOCN, SiBN, SiBO, GeO_(x), GeN, AlO_(X), TiO₂, and TaO₂. The layer canbe formed using one or more of ALD, CVD, PEALD, PECVD, neutral beamenhanced ALD (NBEALD), and neutral beam enhanced CVD (NBECVD), forexample, one or more of PEALD, PECVD, NBEALD, and NBECVD, or one or moreof NBEALD and NBECVD.

A temperature within a reaction chamber during step 102 may berelatively low. For example, a temperature can be less than 400° C.,less than 300° C., less than 200° C., less than 100° C., about 25-40°C., about ambient temperature, about 0 to about 100° C., about 0 toabout 200° C., or about 0 to about 300° C. A pressure within thereaction chamber can be between about 0.01 Pa and about 100 Pa, about0.05 Pa and about 1 Pa, or about 0.1 Pa and about 0.5 Pa.

In some cases, step 102 can include a plasma-enhanced depositionprocess. The plasma can be formed in a plasma chamber. When step 102includes a plasma-enhanced deposition process, a power of an RFgenerator used to form the plasma can be between about 0.1 W/cm² andabout 20 W/cm², about 0.2 W/cm² and about 10 W/cm², or about 1 W/cm² andabout 5 W/cm². When the plasma is formed within a plasma chamber, a biascan be applied to, for example, an aperture plate of a neutral beamapparatus. The bias can be between about 0 W/cm² and about 3 W/cm²,about 0 W/cm² and about 1 W/cm², or about 0 W/cm² and about 0.5 W/cm².

In some cases, step 102 includes a cyclic deposition process, such asone or more of PEALD, PECVD, NBEALD, and NBCVD. In these cases, step 102can be repeated or can include repeating a number of cycles to form alayer of desired thickness. For example, a layer having a thickness ofgreater than zero and less than 10 nm can be formed during step 102.

In accordance with further examples of the disclosure, the layer formedduring step 102 includes silicon. In these cases, a precursor used toform the layer can selected from the group consisting of aminosilanes,such as BDEAS (SiH₂[N(C₂H₅)₂]₂), BTBAS (SiH₂[NHC(CH₃)₃]₂), TDMAS(SiH[N(CH₃)₂]₃), HEAD (Si₂[NHC₂H₆]₆), 3DMASCl (Si[N(CH₃)₂]₃Cl), 3EMAS(H₂Si[N(C₂H₅)CH₃]₃), 4DMAS (Si[N(C₂H₆)₂])₄), 4DEAS (Si[N(C₂H₆)₂]₄), andother Si-containing precursors, such as 4MS ((CH₃)₄Si), 2ES((C₂H₅)₂SiH₂), phenyl-SiH₃, cyclohexyl-SiH₃, Si(OC₂H₅)₄. Additionally oralternatively, the reactant (e.g., an oxidant) can be selected from oneor more of oxygen, CO, CO₂, and NO₂.

During step 104, a neutral beam is generated by introducing a gas to aplasma chamber, forming activated species within the plasma chamber, andpassing the activated species through an aperture plate of a neutralbeam apparatus to generate the neutral beam. In accordance withexemplary aspects of these embodiments, the neutral beam can begenerated from one or more gases selected from the group consisting a ofhydrogen-containing gases (e.g., hydrogen), He, NH₃, O₂, N₂O, CO₂, Ar,Xe, N₂, and their mixture, such as one or more of H₂ and He, andparticularly H₂. By way of particular examples, the neutral beam can begenerated from one or more hydrogen-containing gases (e.g., H₂) andhelium. In these cases, the gas can include about 1 to about 100, about10 to about 100, or about 90 to about 100 percent hydrogen and about 1to about 100, about 10 to about 100, or about 90 to about 100 percenthelium.

During step 106, the layer formed during step 102 is exposed to speciesgenerated from the neutral beam during step 104. Although separatelyillustrated, steps 104 and 106 can overlap and/or occur substantially atthe same time. That is, as species are formed (e.g., within a plasmachamber) during step 104, the (e.g., activated) species can beintroduced to the reaction chamber (e.g., through the aperture plate),such that the layer is exposed to the species generated from the neutralbeam.

A temperature within a reaction chamber during steps 104 and/or 106 maybe relatively low. For example, a temperature can be less than 400° C.,less than 300° C., less than 200° C., less than 100° C., about 25-40°C., about ambient temperature, about 0 to about 100° C., about 0 toabout 200° C., or about 0 to about 300° C. A pressure within thereaction chamber can be between about 0.01 Pa and about 100 Pa, about0.05 Pa and about 1 Pa, or about 0.1 Pa and about 2 Pa.

During step 106, a bias can be applied to an aperture plate of anaperture plate of a neutral beam apparatus during the step of exposingthe layer. By way of examples, the bias can range from about 0 W/cm² toabout 3 W/cm², about 0 W/cm² to about 1 W/cm², or about 0.05 W/cm² toabout 0.2 W/cm².

A power of an RF generator used to form the plasma during step 106 canbe between about 0.1 W/cm² and about 20 W/cm², about 1 W/cm² and about15 W/cm², or about 3 W/cm² and about 10 W/cm².

In accordance with exemplary aspects of these embodiments, steps 102-106can be performed within the same reaction chamber.

FIG. 2 illustrates another method 200 in accordance with exemplaryembodiments of the disclosure. Method 200 includes the steps ofproviding a substrate within a reaction chamber (step 202), providing aprecursor of the reaction chamber to form adsorbed species on a surfaceof the substrate (step 204), providing a reactant to a plasma chamber(step 206), forming a neutral beam from species generated in the plasmachamber (step 208), and exposing the adsorbed species to species fromthe neutral beam to form a layer comprising silicon (step 210).

During step 202, a substrate is provided within a reaction chamber. Thereaction chamber can form part of one or more of an ALD, CVD, PEALD,PECVD, NBEALD, and NBECVD reactor system. For example, the reactionchamber can form part of one or more of PEALD, PECVD, NBEALD and NBECVDreactor system or one or more of NBEALD and NBECVD reactor system.Exemplary reactor systems can include one or more reaction chambers.

During step 202, a substrate or a susceptor upon which a substrate isplaced, can be brought to a desired temperature. For example, thesusceptor can be brought to a temperature of less than 400° C., lessthan 300° C., less than 200° C., less than 100° C., about 25-40° C.,about ambient temperature, about 0 to about 100° C., about 0 to about200° C., or about 0 to about 300° C. A pressure within the reactionchamber during step 202 can be brought to between about 0.01 Pa andabout 100 Pa, about 0.05 Pa and about 1 Pa, or about 0.1 Pa and about0.5 Pa.

During step 204, a precursor is provided to a gas inlet of the reactionchamber. The precursor can react with species on a surface of asubstrate to form adsorbed species on the surface of the substrate. Inaccordance with examples of the disclosure, the precursor is selectedfrom the group consisting of aminosilanes, such as BDEAS(SiH₂[N(C₂H₅)₂]₂), BTBAS (SiH₂[NHC(CH₃)₃]₂), TDMAS (SiH[N(CH₃)₂]₃), HEAD(Si₂[NHC₂H₆]₆), 3DMASCl (Si[N(CH₃)₂]₃Cl), 3EMAS (H₂Si[N(C₂H₅)CH₃]₃),4DMAS (Si[N(C₂H₆)₂])₄), 4DEAS (Si[N(C₂H₆)₂]₄), and other Si-containingprecursors, such as 4MS ((CH₃)4Si), 2ES ((C₂H₅)₂SiH₂), phenyl-SiH₃,cyclohexyl-SiH₃, and Si(OC₂H₅)₄.

A flowrate of the precursor, alone or diluted with a carrier (e.g., aninert gas) to the reaction chamber can range from about 1 sccm to about50 sccm, about 2 sccm to about 20 sccm, or about 4 sccm to about 10sccm.

During step 204, a substrate or a susceptor upon which a substrate isplaced, can be brought to or maintained at a desired temperature, suchas a temperature set forth above in connections with step 202. Apressure within the reaction chamber can be the same or similar to thepressure recited above in connection with step 202.

During step 206, a reactant is provided to a gas inlet of a plasmachamber. Exemplary reactants include one or more of oxygen, CO, CO₂, andNO₂, which can be provided to the inlet of the plasma chamber alone, orin combination with a carrier gas. A flowrate of the reactant gas canrange between about 10 sccm and about 3000 sccm, about 20 sccm and about1000 sccm, or about 30 sccm and about 50 sccm.

During step 206, activated species can be generated from the reactant.In these cases, a bias can be applied to an aperture plate of a neutralbeam apparatus during step 206. The bias can be between about 0 W/cm²and about 3 W/cm², about 0 W/cm² and about 1 W/cm², or about 0 W/cm² andabout 0.5 W/cm².

Although illustrated with step 204 preceding step 206, in some cases,step 206 can precede step 204. In other words, the substrate can becontacted with a reactant first and then a precursor.

As illustrated, steps 204 and 206 can be repeated, as illustrated byloop 212. For example, steps 204 and 206 can be repeated a number oftime until a desired thickness of material is deposited. In some cases,the desired thickness is less than 10 nm.

During step 208, activated species from a neutral beam are formed. Theconditions and reactants for step 208 can be the same or similar to theconditions and reactants described above in connection with step 104. Byway of example, step 208 can include providing gas comprising one ormore of a such as one or more of a of hydrogen-containing gases (e.g.,hydrogen), He, NH₃, O₂, N₂O, CO₂, Ar, Xe, N₂, and their mixture, such asone or more of H₂ and He, and particularly H₂ to the plasma chamber andexposing the layer to species generated from the gas comprising one ormore of a such as one or more of a of hydrogen-containing gases (e.g.,hydrogen), He, NH₃, O₂, N₂O, CO₂, Ar, Xe, N₂, and their mixture.

Similarly, the conditions and reactants for step 210 can be the same orsimilar to the conditions and reactants described above in connectionwith step 106. For example, a bias applied to an aperture plate of aneutral beam apparatus during the step of exposing the layer can bebetween about 0 W/cm² and about 3 W/cm², about 0 W/cm² and about 1W/cm², or about 0.05 W/cm² and about 0.2 W/cm².

Steps 204-210, including loop 212, can be repeated until a layer ofdesired thickness is obtained, as illustrated by loop 214. The thicknesscan be greater than 10 nm.

FIG. 3 illustrates a cross-sectional view of a reactor system 300 inaccordance with exemplary embodiments of the disclosure. Reactor system300 can be configured to perform the steps according to methodsdescribed herein.

In the illustrated example, reactor system 300 includes a reactor 302including a reaction chamber 304, a susceptor 306, a plasma chamber 308,an aperture plate 310, antenna 312, a plasma generation power source314, and a bias power source 316. Reactor system 300 can also include aprecursor gas inlet 318, a reactant gas inlet 320, and an outlet 322,and a controller 328.

Reactor 302 can include any suitable gas-phase reactor. Exemplaryreactors include ALD reactors and CVD reactors, such as those availablein systems provided by ASM International.

Susceptor 306 can be capable of moving vertically to load and unload asubstrate 324. Lift pins and a robot arm (not shown) can be used to loadand unload the substrate from the surface of susceptor 306.

Plasma chamber 308 includes an interior region 326 that is in is influid communication with reaction chamber 304. Plasma generation powersource 314 and antenna 312 can be used to provide, for example, provideradio frequency (RF) power within plasma chamber 308. The RF power canbe used to form a plasma that includes activated species generated fromgas (e.g., reactant gas and/or gas used for treatment of a layer)provided to interior region using, for example, reactant gas inlet 320.Plasma chamber 308 can form part of an inductively coupled plasma (ICP),a capacitively coupled plasma (CCP), electron cyclotron resonance (ECR),surface-wave-sustained discharge (SWP), or neutral loop discharge (NLD)plasma apparatus.

Aperture plate 310 can be used to neutralize the activated speciesformed within plasma chamber 308 prior to activated species enteringreaction chamber 304. To facilitate flow of activated species fromplasma chamber 304 toward susceptor 306 and/or substrate 324, bias powersource 316 can be used to apply a bias voltage to aperture plate 310 toattract ionized species formed within a plasma. Activated species, eventhough neutralized by aperture plate 310 can continue to flow towardsubstrate 324 due, at least in part, to the kinetic energy of thespecies.

Aperture plate 310 can be formed of an electric conductor, such asgraphite. Aperture plate 310 can include a plurality of apertures, whichcan be configured in, for example, a hexagonal configuration.

Precursor gas inlet 318 is used to introduce a precursor gas and/or apurge gas into reaction chamber 304. Although only one precursor gasinlet 318 is illustrated, reactor system 300 can include more than oneprecursor gas inlet 318. For example, multiple precursor gas inlets canbe used to introduce one or more precursors to reaction chamber 304and/or one or more precursors and one or more purge gases to reactionchamber 304.

Reactant gas inlet 320 is used to introduce a reactant gas and/or atreatment gas into interior region 326 of plasma chamber 308. Althoughonly one reactant gas inlet 320 is illustrated, reactor system 300 caninclude more than one reactant gas inlet 320.

Controller 328 can include one or more devices to control power toplasma generation power source 314 and/or bias power source 316.Controller 328 can also be used to control flow of gases—e.g., one ormore gases to precursor gas inlet 318 and/or reactant gas inlet 320,control pressure within reaction chamber 304, control pressure withinplasma chamber 308, and the like. For example, a pressure withinreaction chamber 304 can be controlled by controlling flowrate(s) ofgas(es) into reaction chamber 304 and/or plasma chamber 308 andcontrolling flow through outlet 322. In accordance with various examplesof the disclosure, controller 328 is configured to have system 300perform methods as described herein.

In accordance with additional examples of the disclosure, a structure,such as a structure illustrated in FIGS. 4-7 is provided. The structurecan include a substrate and a layer deposited thereon. Exemplarydeposition and treatment conditions for depositing and treating a layerare provide below in the examples.

EXAMPLES

The examples provided below are meant to be illustrative. Unlessotherwise noted, embodiments of the disclosure are not limited to thespecific examples provided below.

Example 1

For the structures formed according to example 1, an NBEALD process wasused to deposit a layer onto a substrate. Here, a neutral beam apparatuswith 20-cm-diameter aperture plate was used. The NBEALD process includedcyclic repeat of following steps: (1) supplying precursor (aminosilane)to process a chamber and adsorption of the precursor on a substrate, (2)stopping a flow of the precursor supply to the reaction chamber, (3)supplying a reactant (e.g., oxidant) gas to a plasma chamber, (4)generating a neutral beam from the reactant gas and providing activatedspecies from the neutral beam to the substrate, and (5) stoppinggeneration of neutral beam and reactant gas supply. Table 1 shows detailof NBEALD conditions used in example 1.

TABLE 1 NBEALD conditions. Value in this Parameter example RangePrecursor gas Aminosilane 5 sccm Aminosilane 1-50 supply sccm; carriergas (e.g., He, Ar, and/or N₂) may be used Oxidant gas O₂ 30 sccm One orplural of supply oxidizing gas (e.g., O₂, CO, CO₂, or NO₂) and none,one, or plural of inert gas (e.g., He, Ar, N₂), 10-3000 sccm Type ofplasma ICP ICP, CCP, ECR, SWP, NLD generator Frequency of 13.56 MHz 400kHz-3 GHz  plasma generation RF power source Power of plasma 1000 W (3.2W/cm²) 0.1 W/cm2-20 W/cm² generation RF power source Pressure of 0.11 Pa0.01-100 Pa reaction chamber during neutral beam irradiation Pressure of0.41 Pa Any pressure which can plasma chamber generate plasma duringneutral (depending on plasma beam irradiation type) Number of cycles 90any number, depending on desired thickness Frequency of bias 150 kHz50-2000 kHz RF power source Power of bias RF 0 or 100 W (0 or 0-3 W/cm²power source 0.32 W/cm²) Stage temperature 30° C. 0-100° C., or 0-200°C., or 0-300° C.

After formation of the film, a hydrogen neutral beam was irradiated tothe sample using the same apparatus without transferring the sample. Thecondition for the neutral beam treatment of the film is shown in Table2.

TABLE 2 Hydrogen neutral beam irradiation condition. Value in Parameterexample 1 Range Gas supply Hydrogen 75 sccm H2, He, NH₃, O₂, N₂O, CO₂,Ar, Xe, N₂, and their mixture gas, preferably H₂ or He, more preferablyH₂, 10-3000 sccm Type of plasma ICP ICP, CCP, ECR, generator SWP, NLDFrequency of 13.56 MHz 400 kHz-3 GHz  plasma generation RF power Powerof plasma 1300 W (4.1 W/cm²) 0.1 W/cm2-20 W/cm² generation RF powerFrequency of 150 kHz 50-2000 kHz bias RF power Power of bias 0, 20, 40,60 W (0, 0.064, 0-0.5 W/cm², RF power 0.127, 0.191 W/cm²) preferably0.08-0.16 W/cm² Pressure of 1.1 Pa 0.01-100 Pa reaction chamber Pressureof 1.8 Pa Any pressure which can plasma chamber generate plasma(depending on plasma type) Irradiation time 10-40 minutes 10 seconds ormore Stage temperature 30° C. 0-100° C., 0-200° C., 0-300° C., or roomtemperature

WER (wet etch rates) for layers deposited according to the conditionsset forth above in 0.1% hydrofluoric acid were measured. The WER resultsare shown in Table 3. Data for a plasma ALD film and a thermal oxidefilm are also shown in Table 3. As shown, WER of NBEALD film (10 nm) wasdecreased from 1.39 nm/min to 0.39, 0.37, 0.30 nm/min by hydrogenneutral beam irradiation without bias of 10, 25, 40 minutes. Thesevalues correspond to wet etch rate ratios (WERR) of 1.63, 1.54, 1.25.These values are even lower than high temperature (390° C.) PEALD (0.43nm/min).

Bias application during hydrogen neutral beam irradiation was alsotested and results are shown in Table 3. Without bias, WERR was 1.25. Byapplying 20 and 40 W bias, WERR was improved (decreased) to 1.21 and1.17. However, by applying 60 W bias, WERR was increased to 1.67. Notethat this value is still smaller (better) thanno-H₂-neutral-beam-treatment result of 5.79. These results indicate thatthe best bias power, for the conditions set forth above, is 40 W.

Hydrogen plasma irradiation has been used to reform PEALD silicon oxideto reduce WER in 1:1000 (0.05%) HF down to 0.1 nm/min (top, side) and0.2 nm/min (bottom). Since WER of thermal oxide in 1:1000 HF is about0.04 nm/min, these results correspond WERR of 2.5-5. This means thathydrogen neutral beam irradiation can achieve lower WERR. There areseveral possible reasons why neutral beam obtained better results thanplasma, including: (1) plasma (ion) irradiation causes charge-up oftarget film and prevents further introduction of coming ions, whileneutral beam irradiation does not cause charge-up and (2) plasmairradiates strong ultraviolet light which may cause defect generation intarget film, while neutral beam irradiates much less ultraviolet lightand does not generate defects.

TABLE 3 WER and WERR (wet etch rate ratio against thermal oxide) ofvarious silicon oxide films (with and without hydrogen neutral beamirradiation) formed on blanket silicon wafer. Deposition method thermalNBEALD PEALD SiO₂ Deposition condition Bias No bias 100 W 390° C. — H₂neutral beam condition No No No Bias Bias Bias bias, bias, bias, 20 W,40 W, 60 W, N/A 10 min 25 min 40 min 30 min 30 min 30 min N/A N/A N/AWER 1.39 0.39 0.37 0.30 0.29 0.28 0.40 1.01 0.43 0.24 (nm/min) WERR 5.791.63 1.54 1.25 1.21 1.17 1.67 4.21 1.79 —

Application of RF bias power (400 kHz, 100 W) can also decrease WER to1.01 nm/min. However, hydrogen neutral beam irradiation can achieve muchlower WER.

Wet etching using 0.1% hydrofluoric acid was applied also for trenchpattern sample. FIG. 4-7 illustrate cross-sectional STEM images ofstructures 402-708, including layers deposited according to conditionsset forth above, before and after wet etching.

FIG. 4 illustrates structure 402 having features 420, 422 formed withina substrate 418 and a layer 410 formed overlying substrate 418 andstructure 404 having features 424-430 and a layer 412 overlyingsubstrate 418—both without wet etching and structure 406 with features432 and 434 and a layer 414 overlying substrate 418 and structure 408having features 436-442 with a layer 416 overlying substrate 418—bothwith wet etching. No neutral beam irradiation was performed on thesamples illustrated in FIG. 4 .

FIG. 5 illustrates structure 502 having features 520, 522 formed withina substrate 418 and a layer 510 formed overlying substrate 418 andstructure 504 having features 524-530 and a layer 512 overlyingsubstrate 418—both without wet etching and structure 506 with features532 and 534 and a layer 514 overlying substrate 418 and structure 508having features 536-542 with a layer 516 overlying substrate 418—bothafter wet etching. Hydrogen neutral beam irradiation without bias wasapplied to the deposited material to form layers 510-516.

FIG. 6 illustrates structure 602 having features 620, 622 formed withina substrate 418 and a layer 610 formed overlying substrate 418 andstructure 604 having features 624-630 and a layer 612 overlyingsubstrate 418—both without wet etching and structure 606 with features632 and 634 and a layer 614 overlying substrate 418 and structure 608having features 636-642 with a layer 616 overlying substrate 418—bothafter wet etching. Hydrogen neutral beam irradiation with a bias ofabout 20 W was applied to the deposited material to form layers 610-616.

FIG. 7 illustrates structure 702 having features 720, 722 formed withina substrate 418 and a layer 710 formed overlying substrate 418 andstructure 704 having features 724-730 and a layer 712 overlyingsubstrate 418—both without wet etching and structure 706 with features732 and 734 and a layer 714 overlying substrate 418 and structure 708having features 736-742 with a layer 716 overlying substrate 418—bothafter wet etching. Hydrogen neutral beam irradiation with a bias ofabout 40 W was applied to the deposited material to form layers 710-716.

Table 4 summarizes the wet etching results of layers 410-416, 510-516,610-616, and 710-716. As illustrated and as set forth in Table 4, WER ofa feature (e.g., trench) sidewall, in addition to the WER of the top andbottom of the feature, is decreased by neutral beam irradiation. WERIRat different positions (top, side, bottom) are similar. This showseffect of H₂—NB irradiation is isotropic (conformal). Indeed,WER-decreasing effect is even a bit stronger (larger WERIR) at sidewallthan top and bottom. This may be because WER at sidewall is larger andthere is larger margin for decrease of WER, while decrease of WER at topand bottom saturates. Also, this result shows that WER of bottom oftrench pattern with relatively high aspect ratio of 3.3 was decreasedwith similar WERIR.

TABLE 4 WER and WERR of NBEALD silicon oxide with/without H₂ NBdeposited on trench pattern. w/o H₂-NB H₂-NB H₂-NB H₂-NB no bias bias 20W bias 40 W WER top 1.68 0.27 0.24 0.23 (nm/min) side 2.42 0.35 0.290.27 bottom 1.77 0.26 0.26 0.21 WERR (—) top 8.16 1.31 1.18 1.11 side11.76 1.70 1.43 1.33 bottom 8.58 1.25 1.28 1.04 WERIR (—) top — 6.2 6.97.4 side — 6.9 8.2 8.9 bottom — 6.8 6.7 8.2 WER = wet etch rate WERR =wet etch rate ratio, WER(target)/WER(thermal oxide) WERIR = wet etchrate improvement ratio, WER(w/o H₂-NB)/WER(target)

FIG. 8 shows relationship 800 between remaining film thickness andhydrofluoric acid etching time for 10 minutes (line 802), 25 minutes(lines 804), and 40 minutes (lines 806). The relationship was linear, atleast, up to 20 minutes (6-8 nm depth). This means the effect ofhydrogen neutral beam irradiation can reach at least 6-8 nm depth. Byconsidering penetration depth of hydrogen plasma into silicon dioxide,the effect may reach up to about 10 nm depth. So, by repeatingdeposition of silicon oxide film by NBEALD (or other technique) to athickness of less than 10 nm and exposing a formed layer to neutral beamtreatment, high-quality silicon oxide film with thickness more than 10nm can be obtained.

Example 2

For the structures formed according to example 2, SiO₂ layers weredeposited by PEALD onto a substrate. The substrate included planarsurface and trench patterns. The deposition conditions for the PEALDlayers are shown in Table 5.

TABLE 5 PEALD SiO₂ deposition condition. Parameter Value in example 2Precursor Aminosilane (carrier gas: Ar 2 slm) Gas supply O₂ 2 slm, Ar(carrier gas for precursor) 2 slm Pressure 400 Pa Frequency of plasmageneration RF 13.56 MHz power Power of plasma generation RF 50 W (0.071W/cm²) power Discharge time of plasma generation 1.2 s RF power for eachALD cycle State temperature 300° C.

The deposited layers were then exposed to activated species from ahelium neutral beam. Here, a neutral beam apparatus with 10-cm-diameteraperture plate was used. Irradiation conditions are shown in Table 6.

TABLE 6 Helium neutral beam irradiation condition. (Exemplary ranges ofparameters are provided in Table 2, above.) Parameter Value in thisexample 2 Gas supply Helium 10-20 sccm Type of plasma generator ICPFrequency of plasma 13.56 MHz generation RF power Power of plasmageneration 500 W (6.4 W/cm²) RF power Pressure of reaction 0.16-0.30 Pachamber Pressure of plasma chamber Pa Irradiation time 5-40 minutesStage temperature Room temperature or 200° C.

WER of the treated layers in 0.25% hydrofluoric acid were measured. TheWER are shown in Table 7. As a shown, WERR of the layer was decreasedfrom 8.6 to 7.2, 5.1, 4.4, and 3.2 by helium neutral beam irradiation of5, 10, 20, and 40 minutes at 300° C. In case of room temperature, WERRwas decreased from 8.6 to 6.8, 6.4, 6.1, and 4.1 by helium neutral beamirradiation of 5, 10, 20, and 40 minutes. It is shown that He neutralbeam irradiation can decrease WER of silicon oxide, though, in theillustrative examples, the range of decrease is smaller than the rage ofdecrease obtained using H₂ neutral beam irradiation.

TABLE 7 WERR of PEALD silicon oxide films with and without He neutralbeam irradiation formed on blanket silicon wafer He flow 10 sccm 20 sccmPressure 0.16 Pa 0.30 Pa Temperature 300° C. (No Irradiation timeirradiation) 5 min 10 min 20 min 40 min 20 min WERR 8.6 7.2 5.1 4.4 3.26.1 He flow 10 sccm 20 sccm Pressure 0.16 Pa 0.30 Pa Temperature Roomtemperature (No Irradiation time irradiation) 5 min 10 min 20 min 40 min20 min WERR 8.6 6.8 6.4 6.1 4.1 6.5

Table 8 shows WERR of PEALD silicon oxide film deposited on top, side,bottom of trench structure. WERR of top, side, and bottom was decreasedby helium neutral beam irradiation. In case of helium, WERIR of top is abit larger than that of side and bottom, indicating that, for thisillustrative example, He neutral beam irradiation may modify the top ofstructure more strongly than side and bottom surface, unlike H₂ neutralbeam irradiation.

TABLE 8 WERR of PEALD silicon oxide with/without He NB deposited ontrench pattern. Values in parentheses show WERIR (WER improvementratio). with He-NB without He-NB 300° C., Room temperature, Position —20 minutes 20 minutes Top 9.9 3.75 (2.6) 5.63 (1.8) Side 8.9 4.13 (2.2)6.13 (1.5) bottom 9.3 4.38 (2.1) 6.50 (1.4)

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to the embodiments shownand described herein, such as alternative useful combinations of theelements described, may become apparent to those skilled in the art fromthe description. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A method of forming a structure, the methodcomprising the steps of: providing a substrate within a reactionchamber; providing a precursor to a gas inlet of the reaction chamber toform adsorbed species on a surface of the substrate; providing areactant to a gas inlet of a plasma chamber; forming a neutral beam fromspecies generated in the plasma chamber using a neutral beam apparatus;and exposing the adsorbed species to species from the neutral beam toform a layer comprising silicon, wherein the reaction chambertemperature during the step of forming the layer is less than 300° C.,and wherein the precursor is a Si-containing precursor.
 2. The method ofclaim 1, wherein the reactant comprises one or more of oxygen, CO, CO₂,and NO₂.
 3. The method of claim 1, further comprising: providing a gascomprising one or more of a hydrogen-containing gas, helium, ammonia,oxygen, N₂O, CO₂, Ar, Xe, N₂ to the plasma chamber; and exposing thelayer to species generated from the one or more of a hydrogen-containinggas, helium, ammonia, oxygen, N₂O, CO₂, Ar, Xe, N₂.
 4. The method ofclaim 1, wherein the steps of providing a precursor and providing areactant are repeated a number of times prior to the step of exposingthe adsorbed species to species from the neutral beam to form a layercomprising silicon the layer.
 5. The method of claim 1, wherein athickness of the layer is less than 10 nm.
 6. The method of claim 1,wherein the neutral beam apparatus comprises an aperture plate, andwherein the method further comprises a step of applying a bias powerdensity to the aperture plate.
 7. The method of claim 6, wherein thebias power density is between about 0.05 W/cm² and about 0.2 W/cm². 8.The method of claim 1, wherein the precursor comprises an aminosilane.9. The method of claim 1, wherein the precursor is selected from thegroup consisting of BDEAS (SiH₂[N(C₂H₅)₂]₂), BTBAS (SiH₂[NHC(CH₃)₃]₂),TDMAS (SiH[N(CH₃)₂]₃), HEAD (Si₂[NHC₂H₆]₆), 3DMASCl (Si[N(CH₃)₂]₃Cl),3EMAS (H₂Si[N(C₂H₅)CH₃]₃), 4DMAS (Si[N(C₂H₆)₂])₄), 4DEAS(Si[N(C₂H₆)₂]₄), 4MS ((CH₃)₄Si), 2ES ((C₂H₅)₂SiH₂), phenyl-SiH₃, andcyclohexyl-SiH₃, Si(OC₂H₅)₄.
 10. The method of claim 1, wherein apressure within the reaction chamber is between about 0.05 Pa and about1 Pa.
 11. The method of claim 1, wherein the reaction chambertemperature during the step of forming a layer is less than 200° C. 12.The method of claim 1, wherein the neutral beam is generated from one ormore gases selected from the group consisting of hydrogen-containinggases, helium, ammonia, oxygen, N₂O, CO₂, Ar, Xe, and N₂.
 13. The methodof claim 1, wherein the neutral beam is generated from H₂ gas.
 14. Themethod of claim 1, further comprising: repeating the steps of providinga precursor and providing a reactant prior to the step of forming aneutral beam.
 15. The method of claim 14, wherein a thickness of a layerformed during the step of repeating is less than 10 nm.
 16. The methodof claim 1, wherein the layer comprises one or more of an oxide, anitride, and a carbide.
 17. The method of claim 1, wherein the layercomprises one or more of SiO₂, SiN, SiOC, SiCN, SiC, SiON, SiOCN, SiBN,SiBO, GeO_(x), GeN, AlO_(x), TiO₂, and TaO₂.